Bats are widely known as nocturnal mammals, meaning their primary activity occurs between dusk and dawn. The short answer to whether they come out during the day is yes, though it is unusual behavior for a healthy bat. While most bat species adhere strictly to a nighttime schedule, they are sometimes active around twilight—dawn and dusk—a pattern known as crepuscular activity. Seeing a bat flying during the day is a deviation from their normal routine. The reason for this daytime emergence can range from benign environmental factors to serious distress, often warranting closer observation to determine the bat’s condition.
Why Bats Prefer Darkness
The nocturnal lifestyle of bats is an evolved adaptation that offers distinct biological and environmental advantages. The first is the reduced threat from predators that hunt using vision, such as hawks and falcons. Flying in the dark effectively minimizes this predation risk.
Another element is the need for efficient thermoregulation. Bats are highly susceptible to rapid dehydration and overheating under the midday sun due to their small body mass and large surface area. By resting in cool, sheltered roosts during the day, they conserve energy that would otherwise be spent regulating their body temperature.
The night also provides optimal conditions for their primary sensory tool: echolocation. This involves emitting high-frequency sound pulses and interpreting the returning echoes to navigate and hunt insects. The quiet night air reduces acoustic competition from other environmental sounds, allowing the biosonar signals to be clearer and less masked when tracking prey.
Common Scenarios for Daytime Flight
While darkness is preferred, healthy bats occasionally emerge during daylight hours due to external circumstances. One common reason is accidental disturbance of their roosting site. Activities like tree-trimming or construction can abruptly flush bats out of their protected shelter, forcing them to find a new location mid-day.
Bats may also undertake daytime flights during necessary relocation. Colonies sometimes move from one roost to another due to overcrowding, damage, or environmental changes. These movements, particularly during seasonal migration, can result in bats temporarily roosting in exposed locations before continuing their journey at dusk.
Extreme environmental conditions can also prompt a brief daytime emergence. During prolonged drought or high summer temperatures, bats may become severely dehydrated. Driven by thirst or the need to escape an overheated roost, they might risk a short flight before sunset to find water or a cooler microclimate.
When Daytime Activity Signals Trouble
A bat seen during the day is often exhibiting unusual behavior that may indicate sickness or injury. A bat that is grounded, sitting exposed, or struggling to fly is likely distressed. This lethargic, disoriented behavior is a significant warning sign that the animal is not well.
The most concerning possibility when a bat is active during the day is the risk of rabies. Rabies is a viral disease that affects the central nervous system. One classic sign in an infected bat is abnormal behavior, including being active in daylight hours or flying erratically.
If a sick or injured bat is encountered, the most important protocol is to never touch it. Bat teeth are tiny, and a bite or scratch may not be noticeable, yet even minimal contact can transmit the virus. If a bat is found indoors or appears ill, the correct action is to contact local animal control or public health authorities immediately for safe removal and testing, rather than attempting to handle the animal.